<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>弹出层效果</title>
</head>
<link rel="stylesheet" href="./css/index.css">
<script src="./js/index.js"></script>
<body>
   <div id="overflow"></div>
    <input type="button" value="弹出层" id="btn">
    <div id="box">
        <div id="nav">
            <li id="exit">×</li>
        </div>
    </div>

</body>

</html>